Research & Implementation Of C Language Testing System On Machine Based On XML

Programming teaching has been planned to be the second level for thecomputer basic courses teaching schema in the universities. C language hasbeen chosen by many universities or colleges because of its deep impact andbeingusedextensively.Themainreasontoresearchanddevelopthesystemisto instruct and help students grasp and use C language, improve the skills ofprogrammingandgivethecorrectjudgewhenthelessonisfinished.The paper has been illustrating some concepts and theories of the XMLtechnology. The XML technology includes the writing specification of XMLdocuments, the methods of referring the XML documents the entities, theDTD technology when writing the XML documents according to the users'requirement and the XSL technology which is used to invert the XMLdocuments to the HTML documents according to structure of the XMLdocuments.Thecommunicationtechnologymainlydescribeshowtoworkforthe TCP and UDP on the transmission layer. TCP is the protocol whichsupplies the reliable and the connecting oriented bytes flow service. TCPdefines the exchanging data and the acknowledgeable information format,meanwhile it also takes the measure to assure the data to get to the rightdestinations. TCP gives the rule on how to recognize more destinationcomputer processes, how to recovery the missing groups and repetitiongroups when they are wrong. UDP is the protocol which supplies theunreliable and the un-connecting data service. UDPtransports not onlyusers'messages, but the port number between the senders and the receivers, whichassures the correct of processes between the sending processes and thereceiving processes. There is no acknowledgeable, ordering and the flowvolume control for UDP. So the messages sent might be missed, repeated anddisorder. The reliable must be promised by the UDP application.CLIENT-SERVER mode is the cooperation relationships between two logicalsystems (CLIENT and SERVER) and the application. The C/S mode isdividedtwoparts,thefront(CLIENT)andthebehind(SERVER).SERVERisalogicalsystemtosupplyserviceandtheCLIENTisalogicalsystemtosendrequirement. In general, CLIENT sends the application requirements andSERVERresponsestherequirementsandsendstherespondingresults.The paper has completing given the descriptions for the related objectsprocessed. In the testing system, the main processing objects includes thequestions base, the papers extracted form the base, the papers submitted bytheexaminees, thetestingresult evaluatedandtheconfigurationofthetestingsystemwhicharetheXMLformatobjects.AccordingtotheXMLtechnology,thepaperhasprovidedthem.The paper has listed the main algorithms for the testing system, whichare the pattern match algorithm and random data algorithm. The patternmatch algorithm (string match algorithm) is used to seek the position of thesubstring in the main string. The random algorithm is used to produce thesuitable random data. In the testing system, the random data are produced bythe random data algorithm with the student's number as its parameter, whicharestoredonacard.Therandomdataonthecardareusedtobeeachquestionnumber matched the questions in the questions pool. When drawing thequestions, KMP algorithm quickly splits and finds the smaller XML formatdata or the original data. KMP algorithm is a higher efficient match than theconventional pattern match algorithms because it doesn't backdate mainstring and decrease the count of backdating substring. The split proceduresreferred in the system to each XML paper has been calling the KMPalgorithm..For C Language Testing System on Machine Based on XML, an XMLdocument, which is a multi-layer structure, is used by the questions base ofthe system. The XML formal data used between the test section and theservicesectionisthemainfeatureofthesystem.The system takes the conventional C/S mode as its mode and the frontand the behind interface is developed with VB. The XML form data isexchanged during the interaction between the front interface and the behindone finished by the WINSOCK. According to the XML grammar restriction,the data transported is assembled by the program in the XML forminformation added the corresponding open and close tags to the data. Whenthe information arrives, the metadata are split according to its open and closemarkuptagsbythesplittingprogram.There are two important algorithms used in the system which are theRANDOM DATA algorithm and the KMP algorithm. The random data areproduced bythe RANDOM DATAalgorithm with the student's number as itsparameter, which are stored on a card. The random data on the card are usedto be each question number matched the questions in the questions pool.When drawing the questions, KMP algorithm quickly splits and reverts theoriginaldata.KMPalgorithmisahigherefficientmatchthantheconventionalpattern match algorithms because it doesn't backdate main string anddecrease the count of backdating substring. The split procedures referred inthesystemtoeachXMLpaperhasbeencallingtheKMPalgorithm.The system takes the measure which is to embed the test data (saved infiles) in the program segments. After the examinees finish compiling, linkingand running, the C program will read the test data and save the running resultinto a result file. In the questions pool, the correct results for the pre-test datahave been given. When evaluating, the evaluating program scores throughcomparingtheexaminees'answerstotheanswersgiven.It is more important for the system to manage and maintain the XMLquestions pool. To assure the pool integrity, each tag's validness and the datatype legality, the programmer should write the corresponding DTDdocuments to be the specification of writingthe XMLdocument. To add eachquestion to the questions pool, the constructor has to choose questions,program them, choose the test data and its corresponding result, then toassemble them and put it into the pool. The practice has proved that it needsmore work more time, more burdens and more risk to construct the questionspoolfortheconstructor.It is the core idea to take the XML document as the questions base andthe testing papers, which is also the extensible application of the XML. Theidea is a breakthrough for the computer testing system on machine which isoften conventionallyused the database as its questions base. It is creative andexploring for the system to make use of a new question base mode as well.The system has been used by each major in the Agriculture Section of JilinUniversityfor the C Test, which has been sung high praise bythe teacher andstudent.ItisalsohelpfulfortheexamineestopasstheNCRE2ofC.However,there aresome disadvantages forthetestingsystem.Withoutconsidering each question's difficult weight when designing the XMLquestions base,so it is unfairfortheexaminees'papers. Thesystem needs amore intelligent drawing questions algorithm. When drawing questions, thealgorithm should consider some factors which are the computer distributionof the test room, the examinees'position and the difficult weight of eachquestion, etc. The evaluating paper program is lack of personality. Thesystemneedstomoreintelligentevaluatingalgorithmtotolerantsomething.The paper is evaluated by human beings who can tolerant the error such aswritingsomethingwithupperorlowercase,whichthealgorithmshouldcando. The safety of the XML questions base is not high. Because the XMLdocument is a pure text document, it is easyto modifyor destroy byillegalusers. The system like the testing system must solve how to improve theXML questions base safety. If the system will be gradually corrected inusing,it will be a goodhelper forthe C learners andteachers andbea goodserviceforthesecondstageofcomputerbasicteaching.